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Oxygen transmission rate (OTR) is the measurement of the amount of oxygen gas that passes through a substance over a given period. It is mostly carried out on non-porous materials, where the mode of transport is diffusion, but there are a growing number of applications where the transmission rate also depends on flow through apertures of some description. It relates to the permeation of oxygen through packaging to sensitive foods and pharmaceuticals. ==Measurement== Standard test methods are available for measuring the oxygen transmission rate of packaging materials. Completed packages, however, involve heat seals, creases, joints, and closures which often reduce the effective barrier of the package. For example, the glass of a glass bottle may have an effective total barrier but the screw cap closure and the closure liner might not. ASTM standard test methods include: * D3985 Standard Test Method for Oxygen Gas Transmission Rate Through Plastic Film and Sheeting Using a Coulometric Sensor * F1307 Standard Test Method for Oxygen Transmission Rate Through Dry Packages Using a Coulometric Sensor * F1927 Standard Test Method for Determination of Oxygen Gas Transmission Rate, Permeability and Permeance at Controlled Relative Humidity Through Barrier Materials Using a Coulometric Detector * F2622 Standard Test Method for Oxygen Gas Transmission Rate Through Plastic Film and Sheeting Using Various Sensors Other test methods include: * The ambient oxygen ingress rate method (AOIR) an alternative method for measuring the oxygen transmission rates (OTR) of whole packages 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「oxygen transmission rate」の詳細全文を読む スポンサード リンク
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